In a Security User Plane Location (SUPL) service, from the standpoint of market deployment, the SUPL technical specification defined by the Open Mobile Alliance (OMA) organization is mainly to develop a location service based on the technology of a user plane, which mainly includes the function of transmitting assistance location data. The principle of the conventional SUPL technology is described below in conjunction with FIG. 1.
As shown in FIG. 1, according to the SUPL technology defined by the OMA location group, the location system mainly comprises three functional entities: an SUPL service agent, an SUPL Server (SLP) and an SUPL Enable Terminal (SET).
The SET is a terminal that is being located. The SET establishes an SUPL session connection with an SUPL platform (i.e., an SUPL server) in the mode of User Datagram Protocol (UDP)/Internet Protocol (IP), with the corresponding functional interface being the Lup interface and the protocol being the SUPL protocol. Hence, the position information of the SET can be acquired by the SUPL protocol.
The SET may comprise a Mobile Location Server (MLS) application or an SUPL agent. Both the MLS application and the SUPL agent may request the SET to perform a location service through a private interface on a mobile phone terminal or an interface conforming to the Mobile Location Protocol (MLP).
The interface between the SUPL platform and the mobile location application\SUPL agent of a network side is an Le/L1 interface, and the corresponding protocol is the MLP or the Location in Session Initiation Protocol (LOCSIP). In this case, the third-party application system\SUPL agent requests the SUPL platform to perform SET location service through the Le/L1 interface.
The SUPL platform comprises two functional entities: an SUPL Center (SLC) and an SUPL Positioning Center (SPC). When the SUPL platform works in a non-proxy mode, the SLC and the SPC are separated and have a separate interface with the SET respectively. When the SUPL platform works in a proxy mode, there is only one functional interface between the location platform and the SET, i.e., the interface between the SLC and the SET. There is no interface between the SPC and the SET. The SLC serves as the agent between the SPC and the SET. The interface between the SLC and the SPC is the LIP. Due to the roaming of the SET, the SUPL platform may respectively serve as: a roaming location platform, a request location platform, a home location platform, an emergency location platform and the like. Correspondingly, both the SLC and the SPC also have these functions. Besides, the SUPL platform further supports other interfaces, such as, a roaming interface between platforms, an interface between a platform and a computation server, an interface between a platform and a private server, and an interface between a platform and a network layer.
The SUPL agent may provide the application with a function of accessing the location service, and the SUPL agent is the first service access point provided to the outside by the location service system. The application requests to locate one or more SETs through the SUPL agent.
Based on the conventional OMA SUPL architecture described above, the technology for transmitting location data between the SLP and the SET supported by the conventional SUPL technology is described below in conjunction with FIG. 2 and FIG. 3 respectively. It should be noted that the location data here comprises assistance location data and/or position data and the like. The assistance location data comprises: atmospheric model (predicted or real-time), earth magnetic field data, virtual assistance parameter measurements, Advanced Global Navigation Satellite System (AGNSS) data, fingerprint data, radiomap data, measurement data and the like.
As shown in FIG. 2, in the conventional SUPL technology, during a location session initiated by the terminal side, the SET acquires the assistance location data, which is returned by SUPL POS through an SUPL POS INIT request. The SET position data may be computed either by the SET or by the SLP in the SUPL POS process. Finally, the SET acquires the position data, mainly comprising the following steps.
Step S202: The SUPL agent of the SET receives a location request to request the SET to establish a data link.
Step S204: The SET requests a Home SLP (H-SLP) to establish a location session and negotiates the location capability.
Step S206: A target SET sends an SUPL POS INIT message to the H-SLP, wherein the SET can specify the required assistance location data in the message.
Step S208: The H-SLP interacts with the SET by multiple SUPL POS messages, wherein the POS message may carry the required assistance data of the SET.
Step S210: The H-SLP interacts with the target SET by multiple sessions, and the H-SLP or the SET is responsible for position computation and may send the position information to the other party.
Step S212: The H-SLP sends a session ending message to the SUPL agent, and the flow ends.
As shown in FIG. 3, during the long location session with the H-SLP initiated by the terminal, such as a trigger type location service, the assistance location data is requested, and the position data is transmitted. This process mainly comprises the following steps.
Step S302: The SUPL agent of the SET receives a location request to request the SET to establish a data link.
Step S304: The SET requests the H-SLP to establish a location session and negotiates the location capability.
Step S306: The target SET sends an SUPL POS INIT message to the H-SLP, wherein the SET can specify the required assistance location data in the message.
Step S308: The H-SLP interacts with the SET by multiple SUPL POS messages, wherein the POS message may carry the required assistance data of the SET.
Step S310: The H-SLP interacts with the target SET, wherein the interaction message, such as the SUPL POS message, carries the assistance location parameter.
Step S312: After some time, such as in the situation of periodic location or triggered by an event, the SET sends the SUPL POS INIT message to the H-SLP again, wherein the SET can specify the required assistance location data in the message.
Step S314: The H-SLP interacts with the SET by multiple SUPL POS messages, wherein the POS message may carry the required assistance data of the SET.
Step S316: The H-SLP interacts with the target SET, wherein the interaction message, such as the SUPL POS message, carries the assistance location parameter.
It can be seen from what described above that in the related arts, the SUPL technology supports one-time, multiple or continuous (in a solicited mode) location data transmission between the H-SLP and the SET. However, the SET cannot transmit location data with one or more SETs, nor can the assistance data be transmitted between the SET and the SLP for one or more times or continuously in an unsolicited mode.